Studies were centered on biological evaluation of tertiary and quaternary amines which could be considered congeners of choline. These were tested in vitro as potential inhibitors of choline transport and mechlorethamine cytotoxicity in the L1210 and bone marrow progenitor cell system. The bis-quaternary, Cain's Quinolinium (NSC 176319) was a potent inhibitor of HN2 and choline uptake. In the presence of HN2, the combined in vivo toxicities could be reduced for improvement in therapy of the L1210 murine leukemia.